The present invention relates to a herbal medicine useful for the treatment of osteoporosis and other conditions. It may be of use in the prevention or treatment of obesity and diabetes. The medicine is derived from a number of plant materials used in traditional Chinese medicine. More specifically, we have found that a mixture of six herbal materials has desirable activities. Furthermore, the activities of the mixture may be enhanced by fractionation/purification. Desirably the individual herbal materials are fractionated/purified in individually appropriate ways prior to mixing with the other materials.
Osteoporosis is a disease of the skeleton in which the bone loses density. Bones become brittle and prone to fracture. Osteoporosis is diagnosed when bone density has decreased to the point where fractures will happen with mild stress. Bones most likely to break from osteoporosis are in the hip, wrist, and spine. Women past menopause are the group most likely to develop osteoporosis, but it is not uncommon in men over 65.
Bone remodelling is the process in which bones are broken down through resorption and then built back up again through bone formation. This is a natural process that takes place all the time on different parts of skeletal bone. Usually these two processes balance each other out and a stable level of bone mass is maintained. Until a healthy person is around 40, the process of breaking down and building up bone by cells called osteoclasts and osteoblasts is a nearly perfectly coupled system, with one phase stimulating the other. As a person ages, however, or in the presence of certain conditions, this system breaks down and the two processes become unbalanced.
Osteoclasts are specialized bone cells that break down bone mass through a process often called resorption of bone. The action of osteoclasts is balanced by the activity of osteoblasts that build up bone mass. In the bones of healthy adults, bone mass remains relatively stable because osteoblasts and osteoclasts are balancing each other and working together to maintain the bone mass. This allows bones to continuously remodel and to heal when damaged. The function of osteoclasts can be affected by various drugs and key nutrients.
In a recent publication, Lee and colleagues (2007) make the surprising observation that bone, a tissue not previously thought to impact bioenergetics, can affect adiposity, glucose metabolism, and insulin sensitivity. People with obesity and diabetes are known to have abnormalities of bone metabolism. Increased adiposity is a risk factor for fracture in children, and diabetics are prone to fracture, although there is little evidence that they are predisposed to osteoporosis (Schwartz et al., 2001).
However, the rate of bone turnover is decreased in diabetics as reflected by diminished expression of biomarkers of bone resorption and formation, including osteocalcin, an osteoblast specific protein (Gerdhem et al., 2005, Osteoporosis Int., 16, (506-1512). Common thinking holds that the decrease in osteoblast activity (the cells that build bone) results from the consequences of diabetes including hyperglycemia, and decreased levels or effectiveness of insulin and IGF-1 (Inaba, 2004). Lee et al. (2007) now present data to challenge this notion and raise the provocative concept that the reduction in osteoblast function may contribute to obesity and glucose intolerance. In this scenario, a vicious cycle would exist in which the metabolic sequelae of diabetes suppress osteoblast function, leading to diminished osteocalcin bioactivity, which in turn further aggravates obesity and insulin resistance.